1. Field of the Invention
The present invention relates to a process for preparing a sarcocarp (flesh of fruit)-containing jelly, and more particularly, it relates to a process for preparing a sarcocarp-containing jelly including homogeneously dispersed sarcocarps and having natural flavor and the taste of fruit. In particular, it has the taste of fruit without loss of a jelly texture in the mouth.
2. Description of the Prior Art
Recently, the needs of consumers with respect to desserts distributed at a temperature lower than 10.degree. C., hereinafter referred to as "chilled desserts", have been diversified and directed to a higher quality. Even in jelly products, a novel product in which fruit juice contents are increased or a sarcocarp is added in order to use natural materials, a so-called fruit jelly, has been developed and put on the market.
However, there are specific technical problems in the manufacture of the fruit jelly, particularly a sarcocarp-containing jelly, such as how the sarcocarps may be homogeneously dispersed (or distributed) in the jelly. Consequently, in the conventional process, there are several difficulties in the manufacture, and shortcomings in the quality, of the fruit jelly which are as follows.
When starting materials for the manufacture of the jelly (hereinafter referred to as "starting materials" for abbreviation) containing sarcocarps, sugars, gelling agents and other ingredients are added to water, and the mixture is heated to be pasteurized and rapidly cooled to be solidified, the osmotic pressure of the sarcocarps in the above mixture reaches a level equal to that of the liquid portion of the above mixture. However, since the specific gravity of the isotonized sarcocarps is greater than that of the liquid portion of the above mixture, the isotonized sarcocarps precipitate before solidification of the above mixture at the stage of cooling. Therefore, it is impossible to manufacture a jelly in which the sarcocarps are homogeneously dispersed.
In the conventional process, starting materials, such as sugars, acidic constituents, coloring agents and flavoring materials, are dissolved in water, and the sarcocarps are mixed therewith. Then to the resulting mixture containing the sarcocarps are added about 0.5 to 1.0% by weight (hereinafter referred to as "%" for abbreviation) of thickening agents such as locust bean gum and guar gum and about 0.2 to 2.0% of gelling agents such as carrageenan, agar agar, gelatin and pectin. The resulting mixture is heated to prepared a highly viscous mixture. The highly viscous mixture is then stirred and poured into a container whereby the floating or precipitating speed of the sarcocarps in the container is extremely decreased or floatation or precipitation of the sarcocarps in the container is substantially ceased. Then the highly viscous mixture in the container is cooled to be solidified, whereby the sarcocarps are homogeneously dispersed in the jelly.
However, due to the use of a comparatively large amount of thickening agents in the above conventional process, a rubber-like elastic body and markedly pasty texture are given to the fruit jelly. The above body and texture of the fruit jelly obtained by the conventional process are fatal defects for the use of the jelly as a commodity. Furthermore, because of the simultaneous use of thickening agents and gelling agents, the gelation temperature of the gelling agents rises markedly by the synergistic effect of both agents, in comparison with that caused by separate use of the gelling agents. Therefore, the addition of the highly viscous mixture to the container is carried out at a higher temperature. Several disadvantages in the quality of the fruit jelly such as decreased gelling ability of the gelling agents, cause a marked increase of syneresis and disappearance of flavor.
In order to improve the above conventional process having such disadvantages, an attempt was made in which the high viscosity required for homogeneous dispersion of the sarcocarps in the fruit jelly was attained without the use of large amounts of a thickening agent. In this attempt, starting materials with or without the sarcocarps were added to water, heated to pasteurize the mixture, cooled to a temperature somewhat higher than gel-forming temperature (i.e. the highest temperature at which gelation of the mixture containing gelling agent is initiated) of the gelling agent used (for example, gel-forming temperature .+-.2.degree. C. to 3.degree. C.), and poured into a container which continuous stirring to give a shearing stress which maintains the high viscosity of the mixture and homogeneous dispersion of the sarcocarps in the mixture.
In this process, however, rapid gelation occurs as soon as the shearing stress is removed and, therefore, it is necessary that the filling of containers be carried out under continuous stirring or, at least, a shearing stress is continuously applied thereto immediately before the filling. Consequently, it is essential to use a special filling apparatus in which a shearing stress is continuously applied. It is also necessary that the temperature prior to the filling step be maintained in the above-mentioned temperature range. Thus, there is a large restriction imposed upon the manufacture of the product.
As an improvement in the above process, another process is known wherein control of the temperature near gel-forming temperature is not required. In this process, gelling agents are used which react with specific metal ions such as calcium ion to form a reversible gel such that the gel destroyed by applying the shearing stress is restored to the original gel by removing the shearing stress. Once a mixture containing this gelling agent is solidified, a shearing stress is applied thereto to maintain the required high viscosity, while the temperature of the resulting viscous mixture is maintained at a temperature below the gel-forming temperature, then added to a container such that the sarcocarps are homogeneously dispersed. The product is manufactured by utilizing the above mentioned reversibility of the gel. In this process, however, when the excess shearing stress is applied to the gel, even a gelling agent having gel reversibility loses its gelation ability and a long time is required for regelation. Therefore, it is a disadvantage that the amount of the gelling agent used must be increased. Also, there is a restriction in the gelling agent used so that those agents having the texture of jelly in the mouth cannot be always selected for use. Accordingly, this process is not always satisfactory in terms of the quality of the products obtained.
Furthermore, the pH of the mixture prepared for the manufacture of the fruit jelly is low regardless of the presence or absence of the sarcocarp and, when it is heated for pasteurization without any pretreatment, the gelling agents are hydrolyzed and therefore, the use of somewhat larger amount of gelling agents will be required. This generally produces an undesirable effect in terms of taste. This is known to be one of the improvements needed in the manufacture of pasteurized fruit jelly.
Therefore, a need continues to exist for a jelly in which the sarcocarps are homogeneously dispersed and which has the inherent taste and flavor of natural materials without the loss of a jelly texture in the mouth.